(1) Field of the Invention
The present invention relates to a display device, and more particularly, to a liquid crystal display device capable of suppressing a flicker in a low frequency drive.
(2) Description of the Related Art
In a liquid crystal display device, pixels each having a pixel electrode, a thin film transistor (TFT) and the like are arranged in a matrix form in a TFT substrate. Further, a counter substrate is placed opposite the TFT substrate with a liquid crystal interposed between the TNT substrate and the counter substrate. Then, an image is formed by controlling the transmittance of light by liquid crystal molecules for each pixel.
The viewing angle characteristic is a problem for the liquid crystal display device. The viewing angle characteristic is a phenomenon of the change in the brightness or chromaticity between when the screen is viewed from the front, and when it is viewed in an oblique direction. The viewing angle characteristic is excellent the In Plane Switching (IPS) mode for driving liquid crystal molecules by an electric field in the horizontal direction. There are several types of IPS modes. One of such IPS modes is the so-called Fringe Field Switching (FFS) in which, for example, a common electrode is formed in a matted manner on which a comb-shaped pixel electrode is formed with an insulating film between them, to rotate liquid crystal molecules by the electric field generated between the pixel electrode and the common electrode. The FFS mode can achieve a relatively high transmission and is now the mainstream.
A high definition screen is demanded for medium and small sized liquid crystal display devices, in which the area of each pixel is small. When the pixel area is reduced, the value of the additional capacitance may not be enough to stabilize the potential of the pixel electrode. Patent Document 1 (Japanese Patent Application Laid-Open No. 2008-26430) describes a configuration of an FFS type liquid crystal display device in which metal oxide particles with a high relative dielectric constant, such as BaTiO3, are dispersed in an application-type transparent insulating film as an insulating film between a pixel electrode and a common electrode, in order to increase the capacitance while increasing the insulating property of the insulating film.